Description

p21-activated kinase 2 (PAK2) is a member of a family of serine/threonine protein kinase defined by their interaction with the small GTPases, Cdc42 and Rac (1-2). The PAK proteins can be essentially divided into two categories, groups I (PAK1, PAK2 and PAK3) and group II (PAK4, PAK5 and PAK6), based on their structures (3). All six PAKs play an important role in diverse cellular processes, including cytoskeletal dynamics, growth/apoptotic signal transduction through MAP kinases, and regulation of transcription factors (4). The ubiquitous PAK-2 is unique among the PAK isoforms because it is also activated through proteolytic cleavage by caspases or caspase-like proteases (5). Full-length PAK-2 is localized in the cytoplasm, whereas the proteolytic PAK-2p34 fragment translocates to the nucleus. Activation of full-length PAK-2 stimulates cell survival, whereas proteolytic activation of PAK-2p34 is involved in programmed cell death (6).